Dual control for vehicular cranes

ABSTRACT

A dual control for vehicular cranes comprises two separate control units with control levers cooperating in pairs, which levers are protected by casings (7, 7&#39;) consisting of pivotable shell parts (9, 9&#39;) which in a closed position enclose and protect the control levers and in an open position expose the levers. In the two casings (7, 7&#39;) are arranged analogous locking mechanisms (14, 14&#39;) which comprise locking means (15, 15&#39;) being movable between locking and releasing positions. The two locking mechanisms are coupled to a transmission (18) which in a neutral position permits that the one casing (7&#39;) is opened and that in connection therewith transfers the opening motion of the movable shell part (9) to the locking mechanism of the other casing (7) in order to secure its locking means (15) in the locking position and, thereby, make the opening of the other casing (7) impossible as soon as the first one (7&#39;) is opened.

TECHNICAL FIELD OF THE INVENTION

This invention relates to a dual control for vehicular cranes,comprising two control units that are placeable on opposite longitudinalsides of a vehicle and that either comprise a plurality of manuallyactuatable control elements, for instance levers, which cooperate inpairs insofar as the individual control element in the one unit isconnected with a corresponding control element in the other unit, inorder to make possible an activation of a common operating means,independently of whether the one or the other element in a pair ofelements is actuated manually, each control unit comprising a casingarranged to protect the control elements, the casing having ashell-shaped part that is movable between a closed position in which thecontrol elements are enclosed and protected, and an open position inwhich they are accessible from outside.

PRIOR ART

Dual controls of the type as defined in the introduction are previouslydisclosed in, e.g., SE 8201833-4. Further, by prior use it is known toequip the two control units with protective casings consisting of twointer-pivotably movable, shell-shaped parts which in a closed positionenclose and protect the control elements, while they in an open positionpermit the access to the control elements. Moreover, WO 95/16630discloses a protective casing in the form of a simple cover that ispivotable between closing and opening positions.

A drawback in connection with dual controls of the type referred to, isthat they theoretically permit a simultaneous actuation by both controlunits. If the permanent crane operator, normally the vehicle driver,actuates an individual control element in one of the control units, forinstance on the driver's side of the vehicle, it is possible for anotherperson to intentionally or unintentionally actuate another controlelement in the other control unit, on the opposite longitudinal side ofthe vehicle. This implies that the crane could be subjected to motionsthat are not at all intended to be executed by the permanent craneoperator. For instance, said operator could actuate a control elementfor only lowering the crane beam and a load hanging on it, at the sametime as somebody not directly concerned actuates an element comprised inthe opposite control unit, which element makes the crane beam pivotlaterally. In practice, such a situation may of course have disastrousconsequences, for the load object as well as the environment.

OBJECTS AND FEATURES OF THE INVENTION

The present invention aims at eliminating the above mentioned safetyrisk related to previously known dual commands and create the conditionsfor a reliable control of the different functions of the crane.Therefore, a basic object of the invention is to further develop theprotective casings known per se for the two control units of the dualcommand to such an extent that a simultaneous actuation of individualcontrol elements in the units is rendered impossible. One object is alsoto bring about this increased safety by means of simple, mechanicalmeans which are not dependent on the supply of electricity or hydraulicoil.

According to the invention, at least the basic object is attained by thefeatures as defined in the characterizing clause of claim 1.Advantageous embodiments of the invention are further defined in thedependent claims.

BRIEF DESCRIPTION OF THE APPENDED DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a vehicular crane with a dual command,whose two control units are built into protective casings,

FIG. 2 is a partial, enlarged perspective view showing the protectivecasing of the one control unit, in an open state,

FIG. 3 is a schematic view of a first embodiment of the invention, eachone of the two protective casings of the control units being shown in aclosed state,

FIG. 4 is a corresponding view showing one of the protective casings inan open state, at the same time as the other protective casing isclosed,

FIG. 5 is a view corresponding to FIG. 3, showing a second, alternativeembodiment of the invention,

FIG. 6 is a view showing the same embodiment as in FIG. 5, but with theone protective casing open,

FIG. 7 is an enlarged detail view in FIG. 6,

FIG. 8 is a view corresponding to FIGS. 3 and 5, showing a third,alternative embodiment of the invention, both protective casings beingshown in a closed state,

FIG. 9 is a view showing the one protective casing according to FIG. 8in an open state, at the same time as the other protective casing isclosed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In FIG. 1, reference numeral 1 designates generally a crane that ismounted on a carrier 2. The crane comprises a post 3, a lifting beam 4and a jib lever 5. For the control of the different functions of thecrane, a dual control is provided comprising two control units 6, 6',each one of which comprising a number of control elements, which arebuilt into the protective casings 7 and 7', respectively. As may be seenin FIG. 2, each control unit in the example comprises six controlelements 8 in the form of levers, and the protective casing 7 isassembled of two shell-shaped parts 9, 9', which are pivotably movablebetween the closed position as shown in FIG. 1 and the open position asshown in FIG. 2. More specifically, the two shell parts 9, 9' are attheir inner ends interconnected via gear rim segments 10 which attend tothat the shell parts are simultaneously forcedly pivoted aroundappurtenant leading bars 11, 11'.

The control levers 8 in the one unit 6 are connected with thecorresponding levers in the other unit 6', preferably via cross-laidbars 12. Each cooperating pair of levers in the two units may actuate acommon operating means in the form of a hydraulic valve that determinesa desired crane function. In this way, each hydraulic valve may beactivated by either of the two levers in the units 6, 6' which jointlyform a cooperating pair. In other words, the operator may activate adesired crane function independently of on which side of the vehicle heis placed.

In FIGS. 1 and 2 a handle 13 is shown, by means of which the two shellparts of the individual protective casing may be closed and opened,respectively.

As far as the described dual control has been hitherto described, it ispreviously known from SE 8201833-4 and by prior use.

Reference is now made to FIGS. 3 and 4, which show a first embodiment ofthe present invention. In each protective casing, there is arranged alocking mechanism, in its entirety designated by 14 and 14',respectively, said locking means comprising a locking means 15 and 15',respectively, being movable between a locking and a releasing position.Each such locking means cooperates with two wedge-shapedly tapering stopshoulders 16, 17 on the inside of the individual shell parts 9, 9'.Between the locking means 15, 15' extends a transmission in the form ofa bar or rod 18, which at opposed ends is connected to links 20 viajoints 19, the locking means 15, 15' being attached to the free ends ofsaid links. A finger 21 is stiffly connected to each lower shell part 9,which finger is connected to the one end of a draw spring 22, whoseopposed end is connected to an attachment 23 in the form of a sleeveapplied on the bar 18. Advantageously, this sleeve may be movable alongthe bar and adjustable into different positions relative to it by meansof a set screw (not shown).

In FIG. 3, the transmission bar 18 is in a neutral position in which thetwo locking means 15, 15' are distanced from the appurtenant pair ofstop shoulders 16, 17. This implies that the two shell parts 9, 9' intheir respective protective casings are free to be opened without anyobstruction by the locking means 15, 15'. However, if one of theprotective casings, e.g. casing 7', is opened in the way as shown inFIG. 4, viz. by the shell parts 9, 9' being pivoted out from each other,then the transmission bar 18 will be set in motion in the direction ofarrow A. When the lower shell part 9 is pivoted down, then the finger 21serving as a carrier will tension the two draw springs 19, the leftspring making the bar 18 move to the left; something having theconsequence of the locking means 15 being brought into engagement withthe two stop shoulders 16, 17. This implies that the locking means 15,in cooperation with the shoulders 16, 17, locks the two shell parts 9,9' of the casing 7 relative to each other, as soon as the shell parts 9,9' in the other casing 7' have been opened. In other terms, an actuationof the control levers 8 that are within the casing 7 when the controllevers 8 in the opposed protective casing 7' are exposed and accessibleto manual actuation, is made impossible.

When the shell parts of the casing 7' are closed again by pivoting themtowards each other, then the right draw spring 22 guarantees that thetransmission bar 18 returns to the neutral position according to FIG. 3.

In FIGS. 5-7 an alternative embodiment is shown, according to which theindividual locking means 24 has the shape of a pivotable clutch that isconnected with a shaft 25 which in turn is co-rotatively connected withthe previously mentioned handle 13 (see FIGS. 1 and 2). In the example,the handle and the locking clutch 24 are mounted on the lower shell part9 in each protective casing, the clutch 24 cooperating with a stop dowel26 on the inside of the upper shell part 9'. In the region below eachlocking clutch 24 is arranged a detent element 27 in the form of anelastic, bendable plate spring. More specifically, the plate spring 27is L-shaped and has its lower flange 27' attached to the shell part 9.An upstanding upper flange 27" is connected with a transmission elementin the form of a wire 28 that extends between the two protective casings7, 7', suitably accomodated in an encircling tube 29.

In FIG. 5 the transmission wire 28 is shown in a neutral position, inwhich the two detent elements 27 are distanced from the appurtenantlocking clutches 24, so that these may be pivoted without anyobstruction by the detent elements. In this state, the two protectivecasings are closed and the locking clutches 24 are engaged with theappurtenant stop dowel 26.

When one of the two protective casings (in the example, the casing 7')is to be opened, the handle 13 on the shell part 9 in question isturned, whereby the locking clutch 24 is released from the stop dowel26. Then the two shell parts 9, 9' may be pivoted out relative to eachother in the way as shown in FIG. 6. By the pivoting motion of the lowershell part 9, the wire 28 is set in motion in the direction of arrow Bin FIG. 6 and the upstanding bendable flange 27' of the detent element27 in the casing 7 is bent in such a way that it is inserted underneaththe locking clutch 24. As a consequence thereof, a pivoting of thelocking clutch 24 is rendered impossible; something that in turn bringsabout that the two shell halves 9, 9' of the shell 7 cannot be pivotedout and opened.

When the protective casing 7' is closed again, the transmission wire 28automatically returns to the neutral position that is shown in FIG. 3,by the fact that the elastic plate springs forming the detent elements27 take the unloaded starting position in which they are distanced fromthe locking clutches 24.

In FIGS. 8 and 9 is shown a third, alternative embodiment which issubstantially similar to the embodiment according to FIGS. 5 to 7.However, instead of one single transmission wire, two separate wires28', 28" are used here, which suitably are led through separate tubes29' and 29", respectively. The one end of each transmission wire isstill attached to a plate spring 27 serving as a detent element for alocking clutch 24, but the opposed end of the wire is attached to aspecial attachment 30 on the inside of the lower shell part of theopposite protective casing.

The advantages of the invention are evident. By the simple mechanicaltransmission and the locking mechanisms cooperating therewith in the twoprotective casings, an automatic locking is guaranteed by one of theprotective casings as soon as the other one is opened. The locking ofthe non-opened protective casing makes it impossible for any other onethan the crane operator himself to intentionally or unintentionallyactivate any of the functions of the crane.

FEASIBLE MODIFICATIONS OF THE INVENTION

The invention is not restricted solely to the embodiments as describedand shown in the drawings. Thus, it is feasible to apply the inventionalso on protective casings which comprise one sole movable shell part,e.g., a shell part of the type as shown in WO 95/16630. It is alsofeasible to apply the invention in connection with protective casings,whose shell part or parts are movable in another way than by pivoting,e.g., by displacement.

What is claimed is:
 1. In a dual control unit including a first controlunit and a second control unit structured and arranged to be positionedon opposite sides of a vehicular crane, said first and said secondcontrol unit each structured and arranged to include a plurality ofmanually actuable control elements wherein a control element of thefirst control unit will form a pair of control elements with arespective control element of the second control unit for mutualactuation of a respective crane element, said first and second controlunits comprising respective first and second casings structured andarranged to house respective control elements therein and to be movableto a closed position to protect the control elements therein and to bemovable to an open position to provide access to the control elementstherein, wherein the improvement comprises,said first casing comprisinga first locking element and said second casing comprising a secondlocking element, said first and second locking elements each beingmovable between a locked position for locking said first and secondcasing, respectively, and an unlocked position for unlocking said firstand second casing, respectively, means for positioning said first andsecond locking elements in an unlocked position when said first andsecond casings are each positioned in a closed position, and means formoving one of (a) said first locking element to a locked position whensaid second casing is moved to an open position and (b) said secondlocking element to a locked position when said first casing is moved toan open position.
 2. In a dual control unit including a first controlunit and a second control unit structured and arranged to be positionedon opposite sides of a vehicular crane, said first and said secondcontrol unit each structured and arranged to include a plurality ofmanually actuable control elements wherein a control element of thefirst control unit will form a pair of control elements with arespective control element of the second control unit for mutualactuation of a respective crane element, said first and second controlunits comprising respective first and second casings structured andarranged to house respective control elements therein and to be movableto a closed position to protect the control elements therein and to bemovable to an open position to provide access to the control elementstherein, wherein the improvement comprises,said first casing comprisinga first locking element and said second casing comprising a secondlocking element, said first and second locking elements each beingmovable between a locked position for locking said first and secondcasing, respectively, and an unlocked position for unlocking said firstand second casing, respectively, a transmission element extendingbetween and coupled to said first casing and said second casing, saidtransmission element also being coupled to said first locking elementand said second locking element, said first casing comprising at leastone first stop member and said second casing comprising at least onesecond stop member engagable with and disenagable from said first andsecond locking elements, respectively, in said locked and unlockedpositions, respectively, said first and second locking elements beingmovable to an unlocked position and out of engagement with respectivefirst and second stop members when said first and second casings areeach positioned in a closed position, and said transmission elementbeing structured and arranged to one of (a) move said first lockingelement into engagement with said first stop member in a locked positionwhen said second casing is moved to an open position and (b) move saidsecond locking element into engagement with said second stop member in alocked position when said first casing is moved to an open position. 3.The dual contact unit of claim 2 wherein said transmission elementcomprises a bar opposite ends of which are coupled to said first lockingelement and said second locking element, respectively, and furthercomprising a first spring coupled between said transmission element andsaid first casing and a second spring coupled between said transmissionelement and said second casing, said first and second springs beingstructured and arranged to urge said transmission element to a neutralposition to move said first and second locking elements to a respectiveunlocked position when said first and second casings are each positionedin a closed position.
 4. The dual control unit of claim 3 wherein oneend of said bar comprises a first link articulately connected to saidone end, and the opposite end of said bar comprises a second linkarticulately connected to said opposite end, said first locking elementbeing coupled to said first link and said second locking element beingcoupled to said second link.
 5. The dual control unit of claim 2 whereinsaid first locking element comprises an elastic, bendable plate firstspring and said second locking element comprises an elastic, bendableplate second spring, and further wherein said transmission element iscoupled to said first spring and to said second spring, said transitionelement being structured and arranged to (a) bend said first springthereby urging said first locking element against said first stop memberin said locked position when said second casing is moved to an openposition and (b) bend said second spring thereby urging said secondlocking element against said second stop member in said locked positionwhen said first casing is moved to an open position, said first andsecond springs resiling to respective unlocked positions when said firstand second casings are each positioned in a closed position.
 6. The dualcontrol unit of claim 5 wherein said transmission element is a wireextending from said first spring to said second spring.
 7. The dualcontrol unit of claim 5 wherein said transmission element comprises (a)a first wire one end of which is coupled to said first casing and theother end of which is coupled to said second spring, and (b) a secondwire a first end of which is coupled to said second casing and thesecond end of which is coupled to the first spring.
 8. The dual controlunit of claim 5 wherein said first locking element and said secondlocking element further comprise a respective first and second pivotableclutch.
 9. The dual control unit of claim 8 wherein said transmissionelement is a wire extending from said first spring to said secondspring.
 10. The dual control unit of claim 8 wherein said transmissionelement comprises (a) a first wire one end of which is coupled to saidfirst casing and the other end of which is coupled to said secondspring, and (b) a second wire a first end of which is coupled to saidsecond casing and the second end of which is coupled to the firstspring.